发表机构
Rice University; Rice Center for Quantum Materials, Rice University; Extreme Quantum Materials Alliance, Rice University（莱斯大学; 莱斯大学量子材料中心; 莱斯大学极端量子材料联盟）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在CeGaGe中首次实验实现手性Weyl-Kondo半金属态，通过结构相变与Kondo杂化产生内禀反常霍尔电导率，确立了手性、强关联与拓扑共存的平台。
AI 中文摘要
强关联手性材料被提出可承载手性Weyl-Kondo半金属（cWKSM）态，在该态中，Kondo杂化将手性诱导的Kramers-Weyl点交叉以及额外的对称性强制能带交叉钉扎在费米能级附近。实现该态需要一种同时具备晶体手性、非对称性对称性和Kondo关联的材料，而目前尚无已知材料同时满足所有这些要求。在此，我们报告了CeGaGe中cWKSM态的证据，CeGaGe属于RXY（R=稀土；X=Al，Si；Y=Ga，Ge）家族。磁化测量确认在T_N=4.7 K以下存在长程反铁磁序，具有复杂的倾斜磁结构。在已知RXY体系中，CeGaGe独有的特点是发生从非手性四方I4_1md结构（高温下）到手性四方P4_3结构（低温下）的结构相变。CeGaGe中的结构相变使我们能够突出手性在稳定Kramers cWKSM态中的作用。在H || c条件下的霍尔电阻率测量揭示出反常霍尔电导率（AHC），该电导率在Kondo温度T_K≈7 K以下保持恒定，并在高于该温度时急剧下降。这一交叉行为追踪的是Kondo相干性的出现，而非发生在T_N=4.7 K的磁有序。结合对P4_3结构的第一性原理计算，这确认了AHC是由Kondo杂化产生的内禀、Berry曲率驱动的贡献，而非外禀散射或动态标量自旋手性的结果。这些结果确立了CeGaGe作为一个罕见的实验平台，其中晶体手性、强电子关联和非平凡能带拓扑共存，提供了Kondo驱动的cWKSM态的首个材料实现。
英文摘要
Strongly correlated chiral materials have been proposed to host a chiral Weyl-Kondo semimetal (cWKSM) state, in which Kondo hybridization pins chirality-induced Kramers-Weyl point crossings, together with additional symmetry-enforced band crossings, near the Fermi level. Realizing this state requires a material that combines crystal chirality, non-symmorphic symmetry, and Kondo correlations, and currently there are no known materials that combine all these requirements. Here we report evidence for a cWKSM state in CeGaGe, a member of the RXY (R = rare earth; X = Al, Si; Y = Ga, Ge) family. Magnetization measurements confirm long-range antiferromagnetic order below T$_N$ = 4.7 K with a complex, canted magnetic structure. Unique to CeGaGe among the known RXY systems is a structural transition from an achiral tetragonal I4$_{1}$md structure (at high temperatures) to the chiral tetragonal P4$_{3}$ structure (at low temperatures). The structural transition in CeGaGe allows us to highlight the role of chirality in stabilizing the Kramers cWKSM state. Hall resistivity measurements with $H || c$ reveal an anomalous Hall conductivity (AHC) that is constant below the Kondo temperature $T_K \approx 7$ K and drops sharply above it. This crossover tracks the onset of Kondo coherence rather than the magnetic ordering, which occurs at T$_N$ = 4.7 K. Together with first-principles calculations for the $P4_3$ structure, this identifies the AHC as an intrinsic, Berry-curvature-driven contribution generated by Kondo hybridization, rather than a consequence of extrinsic scattering or dynamic scalar spin chirality. These results establish CeGaGe as a rare experimental platform in which crystal chirality, strong electronic correlations, and non-trivial band topology coexist, providing the first material realization of a Kondo-driven cWKSM state.
